Method of attaching covering material to piano action hammer butts, apparatus therefor and article produced thereby



1965 c. w. ANDERSON ETAL 3,236,139

METHOD OF ATTACHING COVERING MATERIAL TO PIANO ACTION HAMMER BUTTS, APPARATUS THEREFOR AND ARTICLE PRODUCED THEREBY 2 Sheets-Sheet 1 Filed April 5, 1965 7 INVENTORS 63 Feb. 22, 1966 C. W. ANDERSON ETAL METHOD OF ATTACHING COVERING MATERIAL TO PIANO ACTION HAMMER BUTTS APPARATUS THEREFOR AND ARTICLE Filed April 5, 1963 PRODUCED THEREBY 2 Sheets-Sheet 2 J J J10 46 J H 96 A /55 3 94 Z I 1:; fi

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0 J05 J03 T 4 g d J00 l :5 1 H a I" d A MW W v INVENTORS (kfiQfTdZfl/MHS/Z J45 6 ug) (Am/a United States Patent Office 3,236,139 Patented Feb. 22, 1966 METHOD OF ATTACHING COVERING MATERIAL TO PIANO ACTION HAMMER BUTTS, APPARA- TUS THEREFOR AND ARTICLE PRODUCED TIIEREBY Clifford W. Anderson and Phillip J. Roehrig, De Kalb, lll., assignors to The Wurlitzer Company, Chicago, III., a corporation of Ohio Filed Apr. 5, 1963, Ser. No. 270,835 18 Claims. (Cl. 84--243) This invention relates generally to the art of manufacturing pianos and analogous musical instruments and relates more particularly to methods and apparatus for attaching covering material to the hammer butts of a piano action assembly. The invention also relates to a novel hammer butt construction.

In the operation of a piano action, the part known variously as a butt knuckle or hammer butt is struck a glancing blow by the part known as the fly or jack. The hammer which is carried by the butt is thus impelled into percussive contact with the corresponding piano string for intoning the desired note; and in accordance with conventional practice, that portion of the butt which is engaged by the fly is provided with a covering material to reduce wear between the parts and preserve proper adjustment of the action. Traditionally, the butt has been covered with buckskin; but more modernly, a high grade of felt is utilized.

In the past, the covering material has been attached by gluing individual pieces to each hammer butt. However, this procedure has proved to be slow and inefficient. Moreover, when resilient padding has been incorporated underneath the covering material, the prior art methods of manufacture have been unable to produce a uniformly tight stretching of the covering material over the padding. Much undesirable variation in the resiliency of the resultant construction has been experienced wtih concomitant lack of uniformity in the response of the butts to the action of their respective jacks.

Therefore, an important object of the present invention is to provide a method of attaching butt covering material in a rapid and uniformly tensioned manner.

A more general object of the invention is to provide a new and improved method of attaching covering material to hammer butts.

Another object of the invention is to provide a method of attaching covering material to a group of aligned hammer butts.

Still another object of the invention is to provide new and improved apparatus for applying covering material to a group of aligned hammer butts.

A further object of the invention is to provide, as an article of manufacture, a hammer butt having improved blow-response characteristics.

A yet further object of the invention is to provide a hammer butt incorporating a covering tightly tensioned over resilient padding,

These and other objects and features of the invention will become more apparent from a reading of the following descriptions.

A method in accord with the invention includes the steps of forming a transverse groove in a hammer butt substantially adjacent one edge of the region thereof which is adapted to be spanked by one end of a cooperating fly in use, applying adhesive material to the groove, wedging one edge portion of a piece of butt covering material into the groove, curing the adhesive material, and contacting the covering material with a gripping element and moving that element to stretch the covering material across the region of the butt which is to be covered. Additionally, the opposite or free edge portion of the covering material is adhesively secured to the hammer butt in continuance of the stretching thereof.

In order that the principles of the invention may be readily understood, reference now should be had to the drawings wherein:

FIG. 1 is a perspective view of a group of hammer butts laterally aligned for receiving both adhesive material and one edge of a strip of butt covering material in grooves provided in the hammer butts for that purpose;

FIG. 2 is an end elevational view of the arrangement of FIG. 1 illustrating attachment of resilient padding in the region underlying the strip of butt covering material and application of adhesive to a shoulder adapted to receive the otherwise free edge of the strip of butt covering material, and illustrating in addition a portion of the press bar which is used in drawing tension into the butt covering material;

FIG. 3 is a view similar to the showing of FIG. 2 but illustrating in particular the action of the press bar;

FIG. 4 is an enlarged perspective view showing cutting of the various materials applied to the grouped parts in producing a finished hammer butt constructed in accordance with the principles of the invention;

FIG. 5 is an enlarged, fragmentary perspective view of the working edge of the press bar;

FIG. 6 is a side elevational view of apparatus arranged to direct the desired movement of the press bar and to provide the desired support of the aligned hammer butts;

FIG. 7 is an enlarged elevational view taken substantially along the line 7-7 of FIG. 6;

FIG. 8 is an enlarged view taken substantially along the line 88 of FIG. 6; and

FIG. 9 is a side elevational view showing a hammer butt assembled into a piano action and further illustrating the cooperation between the covered region of the hammer butt and the end of the associated fiy or jack.

Referring now in detail to the drawings, specifically to FIG. 4, a hammer butt indicated generally by the numeral 20 will be seen to include a rigid body 22 fabricated from a suitable material such as the wood of the hard or sugar maple tree. The body 22 is fashioned with a tongue or mounting formation 24 which is adapted to cooperate in defining a pivot for the hammer butt and therefore for the hammer which is intended to be afiixed to the butt at a bore, not shown. For this purpose, the mounting formation 24 is shaped to define a pair of lateral bosses 28 which are centrally perforated with a bore 30, bore 30 being adapted to receive a pivot pin as will be described more fully hereinafter.

The body 22 of the hammer butt also includes a regiom 32 which is spaced from the formation 24 and which is adapted to be spanked by one end of a cooperating fly or jack in impelling the hammer into percussive engagement with the corresponding piano string. An inclined, flat shoulder 34 is formed adjacent one edge of the region 32 across the body 22; and a transverse groove 36 is cut into the rigid body of the hammer butt at the other edge of the region 32, as by sawing, milling or other suitable means.

In compliance with an important feature of the invention, a piece or short strip 38 of butt covering material is attached to the butt 22 over the region 32, this piece of butt covering material being adhesively attached at one edge in the groove 36 and at the other edge to the shoul der 34. The butt covering material is stretched between these two points of attachment in order that the resultant internal tension in the material may preserve it in a smooth and unwrinkled condition. The butt covering material is advantageously selected from a suitably high grade of mechanical felt, conventional padding felt being too soft and loosely arranged to resist erosion by the 3 action of the end of the fly. A high grade of felt has also proved capable of preserving the tension drawn into the piece of butt covering material upon its initial attachment to the hammer butt.

In further accord with the invention, resilient padding, specifically resilient pads 40 and 42, are secured to the edge surface of region 32 underlying the piece of butt covering material. The pads 40 and 42 are advantageously fabricated from felt; and since these pads are not exposed to wear, the quality of the felt employed is not as critical as it is with the butt covering material. When resilient padding of the described character is affixed to the lateral surface of region 32 underlying the tensioned butt covering material, the tension in the butt covering material acts to compress the padding; and the padding reacts to preserve tension in the covering material. Thus, the hammer butt of the invention displays to the end of the cooperating fly a region which is uniformly resilient and which is resistant to the action of the fly. As a consequence, the hammer butt of the invention exhibits improved blow-responsecharacteristics.

It is to be particularly noted that the groove 36 and the sholuder 34 are arranged to facilitate stretching of the butt covering material from the groove to the shoulder after the covering material has been secured in the groove. The arrangement of the shoulder and the groove particularly accommodates tensioning of the covering material by a single movement of a work member. Specifically, the plane of the shoulder 34 is arranged to intersect the plane of the groove 36 in such a manner as to define an obtuse angle opening toward the body 22.

Turning now to a consideration of FIGS. 1-3 for a more detailed description of the attachment of the butt covering material, a number of the hammer butts 20 are seen grouped together in alignment in FIG. I. The several hammer butts are particularly aligned so that the individual grooves 36 thereof form an elongated channel. A bed indicated generally by the numeral 44 and shown to include a base plate member 46 and a side plate member 48 is advantageously employed in supporting the grouped hammer butts in this position, the plate members 46 and 48 converging to define a right angular repository for the hammer butts.

After the group of hammer butts have been aligned so that the individual grooves 36 form a channel, a suitable glue or adhesive material is applied to the groove from a dispenser such as the squeeze bottle 50; and thereafter, a long strip 52 of the butt covering material has one edge portion thereof wedged into the freshly glued channel, a bladed tool 54 having a serrated edge 56 being usefully employed in this latter regard. It is recognized that the glue or adhesive material may be appropriately disposed between the walls of the grooves 36 and the adjacent surfaces of the edge of strip 52 by coating of the edge of the strip with such material prior to its insertion rather than by the direct application of the adhesive material to the groove in advance of insertion of the strip of butt covering material.

Long strips of felt 58 and 60 are appropriately applied to the aligned hammer butts to form the pads 40 and 42. The strips 58 and 60 are secured by means of a suitable glue or adhesive material and may be affixed to the aligned hammer butts either before or immediately after attachment of the strip 52. The adhesive material used in attaching the strips 52, 58 and 60 is allowed to set or cure prior to tensioning and final attachment of the otherwise free edge of the strip 52.

When the adhesive material has set or cured whereby to affix the strips 52, 58 and 60 to the aligned hammer butts, additional quantities of adhesive material are applied to the aligned shoulders 34 by means of a dispenser 62 shown in FIG. 2. Thereafter, the strip 52 is stretched across the region 32 and over the strips 58 and 60 to be secured to the shoulder 34 by the adhesive material which has been applied thereto. In order to stretch the strip 52 in this manner and dispose it in tensioned condition, a reciprocable press bar or gripping element 64 is directed into glancing engagement with the strip 52 by urging the element in a straight line path indicated in FIGS. 2 and 3 by the arrow 66. It will be noted that the path of movement of the element 64 overlies a front edge portion of the base plate member 46.

In order to insure that the element 64 may properly grip the strip 52 for tensioning the same, an edge portion 68 of the element 64 is cut off to define a working edge or face 70 best shown in FIG. 5. In addition, the face 70 is provided with horizontal grooving 72 to enhance the gripping action of the butt covering material. It is important to note that the grooving 72 is arranged to present in profile a row of flattened teeth or ridges separated by parallel V-grooves. The grip provided by such an arrangement has proved to be uniquely superior to one in which the teeth come to a sharp or knife edge.

Returning to FIGS. 2 and 3, the cut-off edge portion 68 of the press bar element 64 is seen to be disposed at an angle corresponding to the angle of inclination of the shoulder 34. So arranged, the cut-off edge of the press bar element may be used in holding the otherwise free edge of the strip 52 tightly against the shoulder 34 while the adhesive material sets or cures. Tight gripping of the strip 52 at this stage of manufacture preserves the tension drawn into the strip and insures a strong adhesive bond between the strip and the hammer butts. In other words, the otherwise free edge of the strip 52 is adhcsively secured to the several hammer butts at the shoulder 34 in continuation of the stretching of the covering material which comprises the strip 52.

After the strip 52 has been secured in place, the press bar element 64 is retracted from engagement therewith by being moved in a generally upward direction along the path indicated by arrow 66. The group of hammer butts are now connected together by their individual attachment to the strip 52, and the resultant assembly is removed from the elongated bed 44 so that the individual parts may be separated one from the other. Turning to FIG.4, a knife element 74 is seen to be used in severing the strip 52 of butt covering material and the strips of material forming the resilient pads 40 and 42. When a felt pad 76 is to be secured to the hammer butt 20 generally between the groove 36 and the tongue 34, a corresponding strip of felt is attached before use of the knife 74 so that the pad can be incised simultaneously with the strips 52, 58 and 60. A rotary blade may be substituted for the knife 74 if desired.

In accordance with another feature of the invention, the base plate member 46, the side plate member 48 and the press bar element 64 are ,incorporated in apparatus specially adapted for directing proper movement of the press bar relative to the elongated bed formed by the two plate members. Considering FIGS. 6-8. such a machine or apparatus is seen indicated generally by the numeral 80. The apparatus 80 includes end plate members 82 and 84 which upstand from the base plate member 46. In addition, clamp members 86 are disposed at the opposite ends of the base plate member to urge the aligned hammer butts 20 into laterally wedged relationship whereby to immobilize the hammer butts during attachment of the butt covering-material.

Each of the clamp members 86 comprises a threaded stud or bolt 88 which engages a cooperatively threaded aperture in one of the end plate members 82 and 84. A knob 98 is fastened to the outer end of each of-the bolts 88, and'an anti-friction abutment 92 is disposed at the inner end of each of the bolts. Advantageously, the abutments 92 comprise cup-like elements fabricated from nylon for example. Accordingly, the abutments 92 may engage the lateral faces of the endmost hammer'butts to be frietionally attached thereto while at the same time the ends of the bolts 88 may enter the hollows of the respective abutments and turn therein, the material of the abutment providing a bearing surface for the respcctive ends of the bolts.

At their confronting surfaces, the end plate members 82 and 84 carry vertical guide tracks 94; and a portion of the press bar assembly which includes the press bar element 64 is adapted to ride in these guide tracks in order to direct movement of the element 64 toward and away from the underlying edge portion of the base plate member 46. Tht press bar assembly also includes an upper bar element 96 which overlies the element 64. Upper brackets 98 are atfixed to the upper bar 96, and lower brackets 100 are secured to the bar element 64 in individual, vertical alignment with the brackets 98. A bolt element 102 passes slidably through a bore in each of the brackets 98 and 100 for use in securing die springs 104 therebetween. A stop plate 106 is connected to each of the bolts 102 at the opposite ends of the corresponding spring 104 for housing the cut ends of the spring and attaching the spring to the corresponding brackets 98 and 100. This latter arrangement insures a firmly directed downward movement of the press bar element 64 while permitting a certain amount of lateral deflection of the lower end of bar element 64. This deflection of element 64 may also be accommodated by pivotally mounting the element 64 in conjunction with the use of torsion springs.

Operating plates 108 are attached to the upper bar element 96 at the opposite ends thereof, and these plates are formed with rack members 110 which meshingly engage pinions 112. The pinions 112 are mounted on a shaft 114 that spans the apparatus 80 at the upper end thereof, brackets 116 being secured to the end plate members 82 and 84 to support the shaft 114. Advantageously, bearings are mounted in the brackets 116 for journaling the shaft 114. A crank handle 118 is secured to one end of the shaft 114 for rotating the pinions 112 and thereby reciprocating the upper guide bar element 96 by means of the racks 110 and the plate members 108. Handle 118 and its associated parts thus constitute a drive for the press bar assembly. If desired, a brake, a lock or counterweights may be provided in conjunction with the crank handle 118 for securing the same in the position thereof which is associated with operation of the press bar element 64 against the reaction of the aligned shoulders 34 of the hammer butts.

It will be recognized that the apparatus 80 may be readied for use by operating the crank handle 118 to raise the press bar element 64 into its uppermost position. Thereafter, a group of aligned hammer butts 20 will be placed on the base plate member 46 and positioned against the back plate member 48. Thereafter, the knobs 90 will be manipulated to turn the bolts 88 and thereby advance the abutments 92 so as to compress the grouped hammer butts laterally together.

With the press bar element 64 in its uppermost position, ready access will be had to the hammer butts for applying adhesive material to the transverse grooves 36 thereof and for wedging the edge portion of the strip 52 into the channel formed by these grooves. Next, the adhesive material will be set or cured to affix the edge portion of the strip 52. Thereafter, adhesive material will be applied to the shoulders 34 whereupon the handle element 118 will be rotated to lower the press bar element 64 into glancing engagement with the edge of the strip 52. The rotating of the crank handle 118 in the direction indicated in FIG. 7 by the arrow 120 acts to lower the plate member 108 by the interaction of the pinion 112 and the rack 110. Because the upper press bar element 96 is securely fastened to the plate member 108, as by bolts 122 shown in FIG. 7, a resultant lowering of the element 96 through the guides 94 is achieved.

As the upper element 96 is lowered, a corresponding lowering of the press bar element 64 is achieved through the mechanical connection alforded by the die springs 104; and when the press bar element 64 encounters a certain amount of resistance, as by grippingly engaging the strip 52 of butt covering material, it responds by resiliently deflecting away from the aligned butts as is well shown in FIG. 3. This resilient deflection of the press bar element 64 upon grippingly engaging the butt covering material acts to stretch the covering material when further downward movement of the upper element 96 is incurred. After the desired downward travel of the press bar element 64 has been achieved, as may be determined by visual observation, turning of the crank handle 118 will be terminated and a brake applied if one is provided. When the strip 52 has been adhesively secured to the shoulders 34 of the hammer butts 20, the crank handle 118 will be rotated in the reverse direction to raise the press bar elements 64 and 96.

Turning to a consideration of FIG. 9, the finished hammer butts are intended for ultimate assembly in a piano action such as the action indicated generally by the numeral 130. In conventional manner, a main rail 132 extends through the body of the piano to act as a frame member and support the individual action mechanisms. A butt flange 134 is securely mounted to the main rail 132 by a wood screw 136, and the hammer butt 20 is pivotally mounted to the flange 134 by a pin 138 that passes through opposed arms of the butt flange 134 and through the bore formed in the tongue 24 of the ham mer butt, tongue 24 being aligned between these arms. A hammer, not shown, is mounted on the butt 20 by a hammer shank 140 which is received in a bore formed in the butt. Thus, the butt 20 is used in pivotally mounting the hammer so that the hammer may be impelled into percussive contact with the corresponding piano string.

The hammer butt 20 also carries a catcher 142 which is mounted to the butt 20 by a catcher shank 144 in accordance with conventional practice. A fly 146 is mounted to the main rail 132 by means of a whip and a whip flange in further accord with conventional practice; and upon actuation of the fly 146, through the key lever and sticker which are coupled to the whip, the fly moves in the general direction of arrow 148 to impel or rotate the hammer butt 20 in the general direction indicated by arrow 150. The tip of the fly 146 engages the region 32 of the hammer butt which has been covered by the piece 38 of covering material, the action of the tin of the fly on the hammer butt being cushioned by the pads 40 and 42 as has been described.

Rapid and certain response of the hammer butt to the action of the fly is achieved by the construction described, and wear between the parts is minimized, this minimization of wear cooperating with the tension which has been established in the covering material to preserve a given i cfljustment of the action and insure long and satisfactory From the foregoing descriptions, it will be apparent to one skilled in the art that the specific examples herein shown and described are illustrative only. Various changes in structure will, no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. The method of making piano action hammer butts which comprises the steps of: forming a transverse groove in a hammer butt substantially adjacent one edge of the region thereof which is adapted to be spanked by a cooperating fiy in use; inserting one edge portion of a piece of butt covering material into said groove with adhesive material therebetween; curing said adhesive material; contacting said covering material with a gripping element and moving said element to stretch said covering material across said region; and adhesively securing the opposite edge portion of said covering material to said hammer butt substantially adjacent the opposite edge of said region.

2. The method of making piano action hammer butts which comprises the steps of: forming a transverse groove in a hammer butt substantially adjacent one edge of the region thereof which is adapted to be spanked by a cooperating fly in use; applying adhesive material to said groove; wedging one edge portion of a piece of butt covering material into said groove; curing said adhesive material; contacting said covering material with a gripping element and moving said element to stretch said covering material across said region; and adhesively securing the opposite edge portion of said covering material to said hammer butt substantially adjacent the opposite edge of said region.

3. The method of making piano action hammer butts which comprises the steps of: forming a transverse groove in a hammer butt substantially adjacent one edge of the region thereof which is adapted to be spanked by a cooperating fly in use; inserting one edge portion of a piece of butt covering material into said groove with adhesive material therebetween; curing said adhesive material; adhesively securing resilient padding to at least a portion of said region; contacting said covering material with a gripping element and moving said element to stretch said covering material across said region and over said padding slightly compressing said padding; and adhesively securing the opposite edge portion of said covering material to said hammer butt substantially adjacent the opposite edge of said region in continuance of the stretching of said covering material.

4. The method according to claim 1 wherein said covering material is a felt material.

5. The method of making piano action hammer butts which comprises the steps of: forming a transverse groove in each of a plurality of hammer butts susbtantially adjacent one edge of the regions thereof which are adapted to be spanked by cooperating flies in use; orienting a. plurality of the butts with the grooves thereof in alignment forming a channel; inserting one edge portion of an elongated strip of butt covering material into said channel with adhesive material therebetween; curing said adhesive material; contacting said covering material with a gripping element and moving said element to stretch said covering material across said regions; adhesively securing the opposite edge portion of said covering mate rial to said hammer butts substantially adjacent the op posite edge of said regions; and severing said strip of covering material interjacent the individual hammer butts.

6. The method of making piano action hammerbutts which comprises the steps of: forming a transverse groove in each of a plurality of hammer butts susbtantially adjacent one edge of the regions thereof which are adapted to be spanked by cooperating flies in use; orienting a plurality of the butts with the grooves thereof in alignment forming a channel; applying adhesive material to said channel; wedging one edge portion of an elongated strip of butt covering material into said channel; curing said adhesive materiakadhesively .securing resilient padding to at least a portion of said regions; contacting said covering material with a gripping element and moving said element to stretch said covering material across said regions and over said padding slightly compressing said padding; adhesively securing the opposite edge portion of said covering material to said hammer butts substantially adjacent the opposite edge of said regions in continuance of the stretching of said covering material; and severing said covering material and said padding interjacent the individual hammer butts.

7. The method of making piano action hammer butts which comprises the steps of: securing one edge portion of a piece of butt covering material substantially adjacent one edge of the region of the butt which is adapted to be spanked by a cooperating fly in use; moving the surface of a gripping element into glancing engagement with a free portion of said covering material to stretch the same across said region; and adhesivcly securing the opposite edge portion of said covering material to said hammer butt substantially adjacent the opposite edge of said region.

8. The method of making piano action hammer butts which comprises the steps of: securing one edge portion of a piece of butt covering material substantially adjacent one edge of the region of the btttt which is adapted to be spanked by a cooperating fly in use; moving the horizontally grooved surface of a gripping element into resiliently deflectable engagement with a free portion of said covering material to stretch the same across said region; and adhesively securing the opposite edge portion of said covering material to said hammer butt substantially adjacent the opposite edge of said region in continuance of the stretching of said covering material.

9. Apparatus for use in attaching covering material to a group of hammer butts, said apparatus comprising: an elongated bed adapted to be disposed in stationary position, including a base plate member and a side plate member arranged in generally converging relationship to support a plurality of hammer butts in aligned position; and press bar means mounted for rceiprocable movement toward and away from a front edge portion of said base plate whereby glancingly to engage a strip of butt covering material secured at one edge to said aligned butts for stretching said strip over said butts and into position for attachment of its opposite edge to said butts.

10. Apparatus according to claim 9 wherein said press bar means includes an elongated member having a horizontally grooved surface generally facing the juncture of said plate members for grippingly engaging said strip upon downward movement of said press bar means.

11. Apparatus for use in attaching covering material to a group of hammer butts, said apparatus comprising: an elongated bed adapted to be disposed in stationary position, including a base plate member and a side plate member arranged in generally converging relationship to support a plurality of hammer butts in aligned position; clamp means at the ends of said bed acting to urge said aligned butts into laterally wedged relationship; and press bar means mounted for reciprocal movement to ward and away from a front edge portion of said base plate whereby glancingly to engage a strip of butt covering material secured at one edge to said aligned butts for stretching said strip over said butts and into position for attachment of its opposite edge to said butts.

12. Apparatus for use in attaching covering material to a group of hammer butts, said apparatus comprising: an elongated bed adapted to be disposed in stationary position, including a base-plate member and a side plate member arranged in generally converging relationship to support a plurality of hammer butts in aligned positron; press bar means mounted for reciprocal movement toward and away from a front edge portion of said base plate whereby glancingly to engage a strip of butt covering material secured at one edge to said aligned butts for stretching said strip over said butts and into positton for attachment of its opposite edge to said butts, said press bar means including a press bar element, means for reciprocating said press bar element and means mounting said element for deflection upon engagement with the resistance of said positioned butts.

13. Apparatus according to claim 12 wherein said mounting means includes spring means resiliently pivotally mounting said press bar element.

14. apparatus according to claim 9 wherein said press bar means includes a member having a surface generally facing .the juncture of said plate members for grippingly engaging said strip upon downward movement of said press bar. means, said surface being provided with parallel grooves spaced to define intermediate flattened ridges.

15. A hammer butt for use in pivotally connecting a hammer to a piano frame, comprising: a rigid body having a mounting formation adapted to cooperate in defining a pivot and having a region away from said formation adapted to be spanked by one end of the fly in use, said body further having a transverse shoulder at one edge of said region and a transverse groove at the other edge thereof; and a strip of butt covering material stretched between said groove and said shoulder with its opposite ends secured respectively therein and thereto.

16. A hammer butt for use in pivotally connecting a hammer to a piano frame, comprising: a rigid body having a mounting formation adapted to cooperate in defining a pivot and having a region away from said formation adapted to be spanked by one end of a fly in use, said body further having a transverse shoulder at one edge of said region and a transverse groove at the other edge thereof; resilient padding disposed between said shoulder and one edge of said groove; and a strip of butt covering material stretched between said groove and said shoulder with its opposite ends secured respectively therein and thereto, the tension stretched into said 20 strip acting to compress said padding and said padding reacting to preserve tension in said strip.

17. A hammer butt according to claim 15 wherein said butt covering material is felt.

18. A hammer butt for use in pivotally connecting a hammer to a piano frame, comprising: a rigid body having a mounting formation adapted to cooperate in defining a pivot and having a region away from said formation adapted to be spanked by one end of a fly in use, said body further having a fiat transverse shoulder at one edge of said region and a transverse groove at the other edge thereof, the plane of said shoulder intersecting the plane of said groove to define an obtuse angle opening toward said body; and a strip of butt covering material stretched between said groove and said shoulder with its opposite ends secured respectively and in sequence therein and thereto, whereby the relative positioning of said shoulder and said groove acts to facilitate the stretching of said strip to said shoulder in a single movement after said strip has been secured in said groove.

References Cited by the Examiner UNITED STATES PATENTS 497,992 5/1893 Terew 2 84243 508,416 11/1893 Greener 84243 1,525,343 2/1925 Veaco 1443 15 2,670,769 3/ 1954 Zack 144-29 2,807,295 9/1957 Tucker et a1 144-29 25 LEO sM-I Low, Primgry Examiner. 

1. THE METHOD OF MAKING PIANO ACTION HAMMER BUTTS WHICH COMPRISES THE STEPS OF: FORMING A TRANSVERSE GROOVE IN A HAMMER BUTT SUBSTANTIALLY ADJACENT ONE EDGE OF THE REGION THEREOF WHICH IS ADAPTED TO BE SPANKED BY A COOPERATING FLY IN USE; INSERTING ONE EDGE PORTION OF A PIECE OF BUTT COVERING MATERIAL INTO SAID GROOVE WITH ADHESIVE MATERIAL THEREBETWEEN; CURING SAID ADHESIVE MATERIAL; CONTACTING SAID COVERING MATERIAL WITH A GRIPPING ELEMENT AND MOVING SAID ELEMENT TO STRETCH SAID COVERING MATERIAL ACROSS SAID REGION; AND ADHESIVELY SECURING THE OPPOSITE EDGE PORTION OF SAID COVERING MATERIAL TO SAID HAMMER BUTT SUBSTANTIALLY ADJACENT THE OPPOSITE EDGE OF SAID REGION. 